Rotary peristaltic pumps are typically used for moving liquids through flexible tubing. A typical peristaltic pump has a rotor assembly with pinch rollers that apply pressure to the flexible tubing at spaced locations to provide a squeezing action on the tubing against an occlusion bed. The occlusion of the tubing creates increased pressure ahead of the squeezed area and reduced pressure behind that area, thereby forcing a liquid through the tubing as the rotor assembly moves the pinch rollers along the tubing.
The spacing between the occlusion bed and the pinch rollers of the rotor assembly is critical for proper pump operation. The spacing between the occlusion bed and the pinch rollers is unforgiving from a tolerance standpoint since it is used both to provide a compressive force between the rotor assembly and occlusion bed and to locate the occlusion bed with respect to the rotor assembly. Tubing that is too loose in the pump may lead to flapping while tubing that is too tight may lead to excessive wear on the tubing. Improper installation of the tube may lead to poor pump performance and shortened tube life.
A typical peristaltic pump 10 is shown in FIG. 1. Stop tubing 12 is typically required in this type of pump in order to assure the proper length of tubing and tube tensioning inside the pump. Tube stops 14a, 14b are additional retainers that must be assembled onto the tubing at precise intervals that are dictated by the particular pump design. The predetermined distance in between the tube stops 14a, 14b establishes the proper length of tubing within the pump. A problem with tube stops 14a, 14b is that they require users of the pumps to order specialty products. The requirement of the tube stops 14a, 14b is an additional expense that occurs every time tubing 12 is replaced. The added expense is a result of extra parts (stops) and the labor required to precisely install the stops for the particular pump design. Outside of this particular pumping application, the “stop tubing” has no other use.
Other pumps may use retaining systems with retainers having v-shaped notches to hold the tubing, instead of using tube stops, such as the pump disclosed in U.S. Patent Application Publication 2005/0196307 A1, which is incorporated herein by reference in its entirety. These pumps are an improvement over those that require tubing with tube stops as the v-shaped notched clips serve to hold the tubing in place, eliminating the need and added expense of the tube stops. The v-shaped notches work well for a multitude of different tubing sizes and materials. Improvements may be made, however, to the notched retainers that would assist in avoiding any undesired results for large diameter tubing or low durometer tubing materials.
Accordingly, there is a need for a tube retaining system that provides the ability to retain automatically a wide range of tubing diameters and durometers, and provides consistent tube tensioning independent of the type of tube used.